Pinhole mitigation for optical devices

ABSTRACT

Methods, apparatus, and systems for mitigating pinhole defects in optical devices such as electrochromic windows. One method mitigates a pinhole defect in an electrochromic device by identifying the site of the pinhole defect and obscuring the pinhole to make it less visually discernible. In some cases, the pinhole defect may be the result of mitigating a short-related defect.

FIELD

This application claims the benefit of priority to U.S. patentapplication Ser. No. 61/610,241 filed Mar. 13, 2012. Embodimentsdisclosed herein relate generally to optical devices, and moreparticularly to methods and apparatus related to mitigation of pinholedefects in optical devices, for example, electrochromic windows.

BACKGROUND

While electrochromism was discovered in the 1960s, electrochromicdevices still unfortunately suffer various problems and have not begunto realize their full commercial potential. Electrochromic materials maybe incorporated into, for example, windows. Electrochromic windows showgreat promise for revolutionizing the energy sector by affording hugeenergy savings, e.g., by controlling solar heat gain in buildings.

Advancements in electrochromic device technology have increaseddramatically in recent years including ever lower levels of defectivityin the electrochromic device. This is important as defects oftenmanifest themselves as visually discernible, and thus unattractive,phenomenon to the end user. Still, even with improved manufacturingmethods, electrochromic windows have some level of defectivity.Moreover, even if an electrochromic window is manufactured with novisible defects, such visible defects may manifest themselves after thewindow is installed.

One particularly troublesome defect is an electrically short circuitingdefect in an electrochromic window. There are existing methods ofminimizing the visual size of shorting defects, but still there remainsa perceptible defect, though small.

SUMMARY

Herein are described methods and apparatus for mitigating pinholedefects in optical devices, particularly in switchable electrochromicwindows. Certain embodiments include applying a material to theelectrochromic window to obscure the pinhole defects. Embodiments mayinclude changing the nature of the material in the electrochromicdevice, proximate the pinhole, to obscure the pinhole. Methods describedherein may be performed on an electrochromic device of an electrochromiclite prior to incorporation into an insulated glass unit (IGU), afterincorporation into an IGU (or laminate), or both.

Various methods herein can be applied to virtually any optical devicethat includes a material that can be isolable locally or where thedefect is stationary. In some instances, the methods can be implementedon optical devices that have liquid components, as long as the opticaldefect to be obscured is stationary on the device. Using methodsdescribed herein, virtually no visually discernible defects remain tothe observer on the optical device.

These and other features and advantages will be described in furtherdetail below, with reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description can be more fully understood whenconsidered in conjunction with the drawings in which:

FIG. 1A is a schematic cross-section of an electrochromic device in ableached state.

FIG. 1B is a schematic cross-section of an electrochromic device in acolored state.

FIG. 2 is a schematic cross-section of an electrochromic device havingan ion conducting electronically insulating interfacial region ratherthan a distinct IC layer.

FIG. 3 is a schematic cross-section of an electrochromic device with aparticle in the ion conducting layer causing a localized defect in thedevice.

FIG. 4A is a schematic cross-section of an electrochromic device with aparticle on the conductive layer prior to depositing the remainder ofthe electrochromic stack.

FIG. 4B is a schematic cross-section of the electrochromic device ofFIG. 4A, where a “pop off” defect is formed during electrochromic stackformation.

FIG. 4C is a schematic cross-section of the electrochromic device ofFIG. 4B, showing an electrical short that is formed from the pop offdefect once the second conductive is deposited.

FIG. 5A depicts an electrochromic lite having three halo shorting typedefects while the lite is in the colored state, before and after laserscribe to convert the halos into pinholes.

FIG. 5B depicts the electrochromic lite from FIG. 5A, in both coloredand bleached states, after having the three pinholes obscured.

FIG. 6A depicts a perspective exploded view of an IGU assembly having anelectrochromic device on surface 2 of the IGU.

FIG. 6B depicts a cross-section of the window assembly described inrelation to FIG. 6A.

FIG. 6C depicts aspects of methods described herein in relation to thecross-section depicted in FIG. 6B.

FIG. 7 depicts a cross section of a laminated electrochromic lite inrelation to methods described herein.

DETAILED DESCRIPTION

For the purposes of brevity, embodiments described below are done so interms of an electrochromic lite, either alone or incorporated into anIGU or laminate. One of ordinary skill in the art would appreciate thatmethods and apparatus described herein can be used for virtually anyoptical device where a contrast exists between a pinhole defect and thecolored optical device. For context, a description of electrochromicdevices and defectivity in electrochromic devices is presented below.For convenience, solid state and inorganic electrochromic devices aredescribed; however, the embodiments disclosed herein are not limited inthis way.

Electrochromic Devices

FIG. 1A depicts a schematic cross-section of an electrochromic lite,100. Electrochromic lite 100 includes a transparent substrate, 102, aconductive layer, 104, an electrochromic layer (EC layer), 106, an ionconducting layer (IC layer), 108, a counter electrode layer (CE layer),110, and a conductive layer (CL layer), 114. The stack of layers 104,106, 108, 110, and 114 are collectively referred to as an electrochromicdevice or coating. This is a typical, though non-limiting, construct ofan electrochromic device. A voltage source, 116, typically a low voltagesource operable to apply an electric potential across the electrochromicstack, effects the transition of the electrochromic device from, forexample, a bleached state to a colored state. In FIG. 1A, the bleachedstate is depicted, e.g., the EC and CE layers 106 and 110 are notcolored, but rather transparent. The order of layers can be reversedwith respect to the substrate. Some electrochromic devices will alsoinclude a capping layer to protect conductive layer 114, this cappinglayer may be a polymer and/or an additional transparent substrate suchas glass or plastic. In some embodiments, the electrochromic lite islaminated to a mate lite, e.g. made of glass or other material, tintedor not. In some electrochromic devices, one of the conducting layers isa metal to impart reflective properties to the device. In manyinstances, both conductive layers 114 and 104 are transparent, e.g.transparent conductive oxides (TCOs), like indium tin oxide, fluorinatedtin oxide, zinc oxides and the like. Substrate 102 is typically of atransparent or substantially transparent material, e.g. glass or aplastic material.

Certain electrochromic devices employ electrochromic and counterelectrode (ion storage) layers that are complementarily coloring. Forexample, the ion storage layer 110 may be anodically coloring and theelectrochromic layer 106 cathodically coloring. For the electrochromicdevice in lite 100, in the bleached state as depicted, when the appliedvoltage is applied in one direction as depicted, ions, for example,lithium ions are intercalated into ion storage layer 110, and the ionstorage layer 110 is bleached. Likewise when the lithium ions move outof electrochromic layer 106, it also bleaches, as depicted. The ionconducting layer 108 allows movement of ions through it, but it iselectrically insulating, thus preventing short circuiting the devicebetween the conducting layers (and electrodes formed therefrom).

Electrochromic devices, e.g. those having distinct layers as describedabove, can be fabricated as all solid state and inorganic devices withlow defectivity. Such all solid-state and inorganic electrochromicdevices, and methods of fabricating them, are described in more detailin U.S. patent application Ser. No. 12/645,111, entitled, “Fabricationof Low-Defectivity Electrochromic Devices,” filed on Dec. 22, 2009 andnaming Mark Kozlowski et al. as inventors, and in U.S. patentapplication Ser. No. 12/645,159, entitled, “Electrochromic Devices,”filed on Dec. 22, 2009 and naming Zhongchun Wang et al. as inventors,both of which are hereby incorporated by reference in their entirety.

It should be understood that the reference to a transition between ableached state and colored state is non-limiting and suggests only oneexample, among many, of an electrochromic transition that may beimplemented. Unless otherwise specified herein, whenever reference ismade to a bleached-colored transition, the corresponding device orprocess encompasses other optical state transitions suchnon-reflective-reflective, transparent-opaque, etc. Further the term“bleached” refers to an optically neutral state, for example, uncolored,transparent or translucent. Still further, unless specified otherwiseherein, the “color” of an electrochromic transition is not limited toany particular wavelength or range of wavelengths. As understood bythose of skill in the art, the choice of appropriate electrochromic andcounter electrode materials governs the relevant optical transition.

Any material having suitable optical, electrical, thermal, andmechanical properties may be used as substrate 102. Such substratesinclude, for example, glass, plastic, and mirror materials. Suitableplastic substrates include, for example, acrylic, polystyrene,polycarbonate, allyl diglycol carbonate, SAN (styrene acrylonitrilecopolymer), poly(4-methyl-1-pentene), polyester, polyamide, etc. If aplastic substrate is used, it is preferably barrier protected andabrasion protected using a hard coat of, for example, a diamond-likeprotection coating, a silica/silicone anti-abrasion coating, or thelike, such as is well known in the plastic glazing art. Suitable glassesinclude either clear or tinted soda lime glass, including soda limefloat glass. The glass may be untempered, strengthened (by heat orchemically) or otherwise tempered. An electrochromic lite with glass,for example soda lime glass, used as a substrate may include a sodiumdiffusion barrier layer between the soda glass and the device to preventdiffusion of sodium ions from the glass into the device. Both glass andplastic substrates are compatible with embodiments described herein, solong as their properties are accounted for in the methods described.This is explained in further detail below.

FIG. 1B is a schematic cross-section of electrochromic lite 100 shown inFIG. 1A but with the electrochromic device in a colored state (ortransitioning to a colored state). In FIG. 1B, the polarity of voltagesource 116 is reversed, so that the electrochromic layer 106 is mademore negative to accept additional lithium ions, and thereby transitionto the colored state; while at the same time lithium ions leave thecounter electrode or ion storage layer 110, and it also colors. Asindicated by the dashed arrow, lithium ions are transported across ionconducting layer 108 to electrochromic layer 106. Exemplary materialsthat color complimentarily in this fashion are tungsten oxide(electrochromic layer) and nickel-tungsten oxide (counter electrodelayer).

Certain electrochromic devices may include reflective materials in oneor both electrodes in the device. For example, an electrochromic devicemay have one electrode that colors anodically and one electrode thatbecomes reflective cathodically. Such devices are compatible withembodiments described herein so long as the reflective nature of thedevice is taken into account. This is explained in more detail below.

The all solid state and inorganic electrochromic devices described abovehave low defectivity and high reliability, and thus are well suited forelectrochromic windows, particularly those with large formatarchitectural glass substrates.

Not all electrochromic devices have a distinct ion conducting layer asdepicted in FIGS. 1A and 1B. As conventionally understood, the ionicallyconductive layer prevents shorting between the electrochromic layer andthe counter electrode layer. The ionically conductive layer allows theelectrochromic and counter electrodes to hold a charge and therebymaintain their bleached or colored states. In electrochromic deviceshaving distinct layers, the components form a stack which includes theion conducting layer sandwiched between the electrochromic electrodelayer and the counter electrode layer. The boundaries between thesethree stack components are defined by abrupt changes in compositionand/or microstructure. Thus, such devices have three distinct layerswith two abrupt interfaces.

Quite surprisingly, it has been discovered that high qualityelectrochromic devices can be fabricated without depositing a distinctionically conducting electrically insulating layer. In accordance withcertain embodiments, the counter electrode and electrochromic electrodesare formed immediately adjacent one another, without separatelydepositing an ionically conducting layer. It is believed that variousfabrication processes and/or physical or chemical mechanisms produce aninterfacial region between adjacent electrochromic and counter electrodelayers, and that this interfacial region serves at least some functionsof a distinct ionically conductive electronically insulating layer. Suchdevices with such an interfacial region, and methods of fabricating suchdevices, are described in U.S. patent application Ser. No. 12/772,055,filed on Apr. 30, 2010 (now U.S. Pat. No. 8,300,298), U.S. patentapplication Ser. No. 12/772,075, filed on Apr. 30, 2010, and in U.S.patent application Ser. Nos. 12/814,277 and 12/814,279, each filed onJun. 11, 2010—each of the four applications is entitled “ElectrochromicDevices,” each names Zhongchun Wang et al. as inventors, and each ishereby incorporated by reference in their entirety. A brief descriptionof these devices follows.

FIG. 2 is a schematic cross-section of an electrochromic lite, 200,having an electrochromic device in a colored state, where the device hasan ion conducting electronically insulating interfacial region, 208,serving the function of a distinct IC layer. Voltage source 116,conductive layers 114 and 104, and substrate 102 are essentially thesame as described in relation to FIGS. 1A and 1B. Between conductivelayers 114 and 104 is a graded region, which includes counter electrodelayer 110, electrochromic layer 106 and an ion conducting electronicallyinsulating interfacial region, 208, between them, rather than a distinctIC layer. In this example, there is no distinct boundary between counterelectrode layer 110 and interfacial region 208, nor is there a distinctboundary between electrochromic layer 106 and interfacial region 208.Collectively, regions 110, 208 and 106 may be thought of as a continuousgraded region. There is a diffuse transition between CE layer 110 andinterfacial region 208, and between interfacial region 208 and EC layer106. Conventional wisdom was that each of the three layers should belaid down as distinct, uniformly deposited and smooth layers to form astack. The interface between each layer should be “clean” where there islittle intermixing of materials between adjacent layers at theinterface. One of ordinary skill in the art would recognize that in apractical sense there is inevitably some degree of material mixing atlayer interfaces, but the point is, in conventional fabrication methodsany such mixing is unintentional and minimal. The inventors of thistechnology found that interfacial regions serving as IC layers can beformed where the interfacial region includes significant quantities ofone or more electrochromic and/or counter electrode materials by design.This is a radical departure from conventional fabrication methods.

The all solid state and inorganic electrochromic devices described abovehave low defectivity and high reliability. However, defects can stilloccur. For context, visually discernible defects in electrochromicdevices are described below in relation to conventional layered stacktype electrochromic devices so as to more fully understand the nature ofthe embodiments disclosed herein. Embodiments described herein apply toother electrochromic devices such as those employing organic polymers,laminated devices, and the like, as well as other optical devices, solong as there is a pinhole type defect that can be obscured.

Visible Defects in Electrochromic Devices

As used herein, the term “defect” refers to a defective point or regionof an electrochromic device. Defects may be characterized as visible ornon-visible. Often a defect will be manifest as a visually discernibleanomaly in the electrochromic window or other device. Such defects arereferred to herein as “visible” defects. Typically, these defects arevisible when the electrochromic device is transitioned to the tintedstate due to the contrast between the normally operating device area andan area that is not functioning properly, e.g., there is more lightcoming through the device in the area of the defect. Other defects areso small that they are not visually noticeable to the observer in normaluse. For example, such defects do not produce a noticeable light pointwhen the device is in the colored state during daytime. A “short” is alocalized electronically conductive pathway spanning the ion conductinglayer or region (supra), for example, an electronically conductivepathway between the two transparent conductive oxide layers.

In some cases, an electrical short is created by anelectrically-conductive particle lodging in the ion conducting layer,creating an electronic path between the counter electrode and theelectrochromic layer or the conductive layer associated with either oneof them. In some other cases, a defect is caused by a particle on thesubstrate (on which the electrochromic stack is fabricated) and such aparticle causes layer delamination (sometimes called “pop-off”) wherethe layers do not adhere properly to the substrate. A delamination orpop-off defect can lead to a short if it occurs before a conductivelayer or associated EC or CE is deposited. In such cases, thesubsequently deposited conductive layer or EC/CE layer will directlycontact an underlying conductive layer or CE/EC layer providing directelectronic conductive pathway. Both types of defects are illustratedbelow in FIGS. 3 and 4A-4C.

FIG. 3 is a schematic cross-section of an electrochromic lite 300 havingan electrochromic device with a particle, 302, in and spanning the ionconducting layer causing a localized shorting defect in the device. Theelectrochromic device in lite 300 is depicted with typical distinctlayers, although particles in this size regime would cause visualdefects in electrochromic devices employing ion conductingelectronically insulating interfacial regions as well. Electrochromicdevice of lite 300 includes the same components as the electrochromicdevice depicted in FIG. 1A. In ion conducting layer 108 of theelectrochromic device of lite 300, however, there is a conductiveparticle 302 or other artifact causing a defect. Conductive particle 302results in a short between electrochromic layer 106 and counterelectrode layer 110. This short affects the device locally in twoways: 1) it physically blocks the flow of ions between electrochromiclayer 106 and counter electrode layer 110, and 2) it provides anelectrically conductive path for electrons to pass locally between thelayers, resulting in a transparent region 304 in the electrochromiclayer 106 and a transparent region 306 in the counter electrode layer110, when the remainder of layers 110 and 106 are in the colored state.That is, if electrochromic device of lite 300 is in the colored state,where both electrochromic layer 106 and ion storage layer 110 aresupposed to be colored, conductive particle 302 renders regions 304 and306 of the electrochromic device unable to enter into the colored state.These defect regions are sometimes referred to a “halos” or“constellations” because they appear as a series of bright spots orstars against a dark background (the remainder of the device being inthe colored state). Humans will naturally direct their attention tohalos due to the high contrast of halos against a colored window andoften find them distracting and/or unattractive. As mentioned above,visible shorts can be formed in other ways.

FIG. 4A is a schematic cross-section of an electrochromic lite, 400,having an electrochromic device with a particle, 402, or other debris onconductive layer 104 prior to depositing the remainder of theelectrochromic stack. Electrochromic device of lite 400 includes thesame components as electrochromic device of lite 100. Particle 402causes the layers in the electrochromic device stack to bulge in theregion of particle 402, due to conformal layers 106-110 being depositedsequentially over particle 402 as depicted (in this example, transparentconductor layer 114 has not yet been deposited). While not wishing to bebound by a particular theory, it is believed that layering over suchparticles, given the relatively thin nature of the layers, can causestress in the area where the bulges are formed. More particularly, ineach layer, around the perimeter of the bulged region, there can bedefects in the layer, for example in the lattice arrangement or on amore macroscopic level, cracks or voids. One consequence of thesedefects would be, for example, an electrical short betweenelectrochromic layer 106 and counter electrode layer 110 or loss of ionconductivity in ion conducting layer 108. These defects are not depictedin FIG. 4A, however.

Referring to FIG. 4B, another defect that may be caused by particle 402is called a “pop-off.” In this example, prior to deposition ofconductive layer 114, a portion above the conductive layer 104 in theregion of particle 402 breaks loose, carrying with it portions ofelectrochromic layer 106, ion conducting layer 108, and counterelectrode layer 110. The “pop-off” portion is piece 404, which includesparticle 402, a portion of electrochromic layer 106, as well as ionconducting layer 108 and counter electrode layer 110. The result is anexposed area of conductive layer 104. Referring to FIG. 4C, after the“pop-off” and once conductive layer 114 is deposited, an electricalshort may be formed where conductive layer 114 comes in contact withconductive layer 104. This electrical short would leave a transparentregion or halo in the electrochromic device of lite 400 when it is inthe colored state, similar in appearance to the defect created by theshort described above in relation to FIG. 3.

Typically, a defect causing a visible short will have a physicaldimension of about 3 micrometers, sometimes less, which is a relativelysmall defect from a visual perspective. However, these relatively smalldefects result in a visual anomaly, the halo, in the coloredelectrochromic window that are, for example, about 1 cm in diameter,sometimes larger. Halos can be reduced significantly by isolating thedefect, for example circumscribing the defect via laser scribe or byablating the material directly without circumscribing it. For example, acircular, oval, triangular, rectangular, or other shaped perimeter isablated around the shorting defect thus electrically isolating it fromthe rest of the functioning device. The circumscription may be onlytens, a hundred or up to a few hundred microns in diameter. Bycircumscribing the defect, and thus electrically isolating the defect,the visible short will resemble only a small point of light to the nakedeye when the electrochromic window is colored and there is sufficientlight on the other side of the window. When ablated directly, withoutcircumscription, there remains no electrochromic device material in thearea where the electrical short defect once resided. Rather, there is ahole in the device and the base of the hole is, e.g., the float glass orthe diffusion barrier or the lower transparent electrode material, or amixture thereof. Since these materials are all transparent, light maypass through the base of the hole in the electrochromic device.

Depending on the diameter of a circumscribed defect, and the width ofthe laser beam, circumscribed pinholes may also have little to noelectrochromic device material remaining within the circumscription (asthe circumscription is typically, though not necessarily, made as smallas possible). Such mitigated short defects manifest as pin points oflight against the colored device, thus these points of light arecommonly referred to as “pinholes.” Isolation of an electrical short bycircumscribing or direct ablation would be an example of a man-madepinhole, one purposely formed to convert a halo into a much smallervisual defect. However, pinholes may also arise as a natural result ofdefects in the electrochromic device.

Generally, a pinhole is a region where one or more layers of theelectrochromic device are missing or damaged so that electrochromism isnot exhibited. Although pinholes may naturally occur as a result ofdefects in an electochromic device, pinholes are not themselveselectrical shorts, and, as described above, they may be the result ofmitigating an electrical short in the device. A pinhole may have adefect dimension of between about 25 micrometers and about 300micrometers, typically between about 50 micrometers and about 150micrometers, and thus is much harder to discern visually than a halo.Typically, in order to reduce the visible perception of pinholesresulting from mitigation of halos, one will limit the size of apurposely-created pinhole to about 100 micrometers or less. However,embodiments described herein allow pinholes to be larger because thepinholes are obscured from view. One aspect of the embodiments disclosedherein is to reduce, if not eliminate, the number of visual defects theend user actually observes, particularly, to obscure pinholes, whethernaturally occurring or purposely made from mitigation of halos. Variousembodiments are described in more detail below.

FIG. 5A depicts an electrochromic lite, 500, having three halos fromshorting-type defects in the viewable area of the lite while the lite isin the colored state. The lite on the left side of FIG. 5A shows thehalos prior to mitigation to make them visually smaller. The lite on theright side of FIG. 5A shows pinholes after the electrical short defectscausing the three halos have been directly ablated or circumscribed toform pinholes. As depicted, and described above, the halo defects arevery noticeable due to their relative size as compared to thedarkly-colored remainder of the electrochromic lite. In this example,electrochromic device on lite 500 might have an area, e.g., on the orderof 24 inches by 32 inches. The transparent border around the darkenedarea represents a perimeter portion of the lite which does not haveelectrochromic device on it. For example, a mask is used duringdeposition of the device and/or a portion of the device has been removedfrom the perimeter after deposition, for example, using an edgedeletion, for example, mechanical or via laser ablation. The lite on theright, where the three halos have been mitigated to pinholes,exemplifies the drastic improvement in reducing the size of the visualdefects from halos to pinholes. Embodiments described herein go furtherto eliminate the visual perception of pinholes.

In one embodiment, pinholes are obscured by application of a material tothe site of the pinhole, e.g., an ink, paint or other material thatcovers the spot where the pinhole exists. The material may be applied,for example, via an ink jet technology. For example, when mitigatinghalos on an electrochromic lite, a laser mitigation device may bemounted on an X-Y stage and include an optical detection device thatlocates the shorting defects causing the halos. The coordinates of thedefects are stored in a memory and fed to the laser tool, which thenablates material around or at the site of the defect in order to isolatethe defect and create a pinhole. The same defect coordinates can then beused to supply an ink jet dispenser with the location of the defect, andthus the site of the pinhole. The ink jet dispenser then covers eachpinhole with an ink, e.g., an opaque or translucent ink. The materialapplied to the pinholes may approximate the color of the colored ECdevice, or not, depending on the application. In some embodiments,covering the pinhole with the material can be done manually. Ink jettechnology is particularly well-suited for this application as it candeliver a precise volume of a material in a precise area using precisecoordinates.

FIG. 5B depicts the electrochromic lite from FIG. 5A, in both coloredand bleached states, after having the three pinholes obscured. The leftlite is colored, showing that once the pinholes are covered, in thisexample with an ink that approximates the color and the transmittance (%T) of the darkened electrochromic device, they cannot be seen by the enduser. The right lite shows that when the lite is bleached, the materialobscuring the pinholes is very small, being visually discernible only asvery small spots on the window (the dots in FIG. 5B are drawn largerthan may be needed so they can be seen for the purposes of illustrationonly). For example, the spots of material used to obscure the pinholesmay be as small as 50 micrometers in diameter. It is difficult todiscern a 50 micrometer spot on a window, and not only because of itssmall size. Although the contrast between the spots of material and thebleached lite is still high (as between the pinholes and the coloredlite), the spots are less noticeable since the incoming light diffusesand scatters around the small spots, making them hard to see by thenaked eye. In embodiments where the ink spots are translucent, they arenearly imperceptible to the human eye.

The material added to the site of the pinhole may be slightly smaller(e.g., smaller by less than 1%) than the pinhole area, smaller than thepinhole area (e.g., smaller by greater than 1%), the same area orsubstantially the same area as the pinhole area, or larger than thepinhole area. In certain embodiments, the area of the material appliedto the site of the pinhole exceeds the area of the pinhole by about 10percent, in another embodiment by about 20 percent, and in yet anotherembodiment by about 50 percent. As mentioned, ink jet technology is oneexcellent method of applying the material, as this technology is wellcharacterized and able to add very small amounts of material to asurface with high precision.

The material used to obscure the pinhole may be of a particular color,e.g., black, white, gray, green, brown or blue. The material used toobscure the pinholes need not be opaque. In certain embodiments, thematerial is translucent. The goal in this embodiment is to reduce thehigh contrast between the pinhole and the colored window, while alsoreducing the contrast between the bleached window and the material. Forexample, if the material's opacity (and, e.g., color) approximate theopacity of the window at 50% of its maximum absorptive state (minimum %T), it will significantly reduce the ability of an end user to visuallydiscern the pinhole, while not completely blocking all the lightemanating from the pinhole. Likewise, since the material is not as darkas the window could be in its darkest state, when the window is bleachedthe material will be harder to see because it doesn't contrast asgreatly against the transparent window. Thus, for example, the materialmay simply be a gray, or gray blue or blue tinted material applied tothe pinhole. Given that pinholes aren't particularly easy to see due totheir size, although still visually discernible, applying even a lightlytinted material (relative to bleach state of window) to the pinholesdrastically reduces the visual perception of the pinholes. This alsomakes the material hard to discern against the bleached window as abackground. Thus a variety of colors for the material can be used toobscure the pinholes. In one embodiment the material is white. Whitematerial, whether opaque or translucent, will still block some or all ofthe incoming light in a pinhole, and be very hard to see when the liteis bleached. In some embodiments, the material applied to the pinholesis robust, i.e. able to withstand the heat and radiation as would beexpected on an exterior window in a building.

In fact, the material need not be colored at all. In one embodiment, thematerial is configured to scatter the light coming through the pinhole.Thus, rather than a beam of light, which naturally passes through atransparent substrate at the pinhole and is easier to see by the enduser, the light is scattered at the surface of the glass at the originof the pinhole, thus making the pinhole harder to see. This may beachieved, e.g., by applying a material to the pinhole having smallparticles that scatter the light. A diffuse light emanating from thepinhole is much harder to discern by the eye than a beam of lightwithout such scattering. Also, during bleached states, the lightscattering material is also harder to discern on the bleached litebecause, e.g., the particles can be transparent while still scatteringthe light passing through them.

In certain embodiments, the material is configured to scatter the lightcoming from the pinhole and the material has at least some tint (lower %T) relative to the window lite in its bleached state. For example,particles, e.g. applied as a slurry with adhesive, are applied to thepinhole. The particles can be transparent, translucent or opaque. Theparticles can be colored or not. In one embodiment, the particles aremade of a material that has a lower % T than the electrochromic lite inits bleached state, i.e., they are translucent or transparent andcolored. In another embodiment, the adhesive adds a tinting element tothe material applied to the pinhole. In another embodiment, both theparticles and the adhesive include a tinting element to the materialadded to the pinhole. In one embodiment, the material applied to thepinhole comprises only an adhesive, no particles are added. In oneembodiment, the adhesive is applied as a foam or otherwise withentrapped gas bubbles. When the adhesive dries or cures, the bubbles mayremain trapped in the adhesive, or may leave cavities, giving theadhesive the ability to bend or scatter light passing therethrough.

In certain embodiments, the material added to the pinhole includes or isa thermochromic material, e.g., a leuco dye, an ink, a paint, a polymer,a metal oxide (e.g. titanium dioxide, zinc oxide, vanadium oxide,mixtures thereof, and the like). The material may have one or more ofthe properties above such as light scattering particles, or not, butincludes a thermochromic element. In one example, the material has aclear, neutral or translucent property at low temperatures, but darkensupon heating, for example, above room temperature. When the EC lite istransitioned to a colored state, e.g. to block solar heat gain on asummer day, the thermochromic material also darkens to obscure thepinholes due to the heating at the electrochromic lite due to absorptionof energy. In one embodiment, where the material added to the pinholehas a thermochromic and a light scattering property, the lightscattering property will aid not only in hiding the pinhole when thelite is colored, but also obscure the material when the lite isbleached.

In another embodiment, no material is added to the site of the pinhole,rather the substrate and/or the electrochromic device material arealtered to make a “better” pinhole, i.e. one that is less visuallydiscernible. That is, rather than simply circumscribing or ablating theelectrical short defect and creating a pinhole, in certain embodiments,the substrate bearing the electrochromic device and/or the material inthe area of the short are manipulated to create an area that has theproperties of an obscured pinhole. This manipulation may or may notinclude circumscription of the defect. Thus electrochromic devicematerial is purposely left in the area of the short defect, but it,along with the short defect, is converted to a non-active device areathat has some ability to block or at least modify the light that wouldotherwise pass through the area of the pinhole without such modification(such as lower % T or scattering the light).

In one embodiment, the electrochromic stack material proximate theelectrical short (which may include a particle or other defect in the ECdevice) is subjected to an energy source to change the properties of thematerial locally in order to obscure light and/or change the % T in thatlocalized area. In one embodiment, this change in material property isperformed without also circumscribing the area. In one embodiment, thismaterial change in property is done with circumscribing, before, duringor after the energy source is applied to change the properties of thedevice locally. For example, a laser is used to melt or otherwise changethe physical and/or optical properties of the device proximate ashorting defect. The laser might have a more diffuse focus and/or lesspower than would be used to ablate material for creating a pinhole viacircumscribing the defect. After the material is changed locally, alaser, e.g. the same laser with the focus and/or power adjustedaccordingly, is used to circumscribe the area with the changed materialproperty. In this example, the change in the material inside (and/oroutside) the circumscribed area changes the optical properties of thematerial locally so that the pinhole is not as discernible to the user.In one embodiment, the laser energy is applied so as to convert a metaloxide to a metal or a lower oxide state, thus making the material lesstransmissive.

In one embodiment, the electrochromic device material is subjected to alower energy laser than would normally be used to ablate theelectrochromic device material from the pinhole. In this case, thedefect may be isolated, but the electrochromic material may remain inthe isolated region, e.g., as small particles which result from breakingup of the electrochromic device locally. The small particles may scatterthe light passing through the pinhole (e.g. as described above).

In another embodiment, the circumscription is performed to isolate ashorting defect. Then, the material inside the pinhole formed by thecircumscription is subjected to an energy source to, e.g., melt it sothat it fills the area of the shorting defect and also at least anablation circle (or other shape) so that light that would otherwise passthrough at the site of the pinhole must also pass through the materialwith the changed properties and thus will have, e.g., lower % T and/orbe scattered or diffuse so that it is less noticeable to the end user.

In one embodiment, a shorting defect, rather than being circumscribed orablated directly with a laser, is treated with a more diffuse energysource, such as a laser that is less focused and/or has less power. Thematerial proximate the short, i.e. the EC device stack including atleast the top transparent electrode, is made non-functional due to theenergy application. For example, the device is melted locally so thatthere is material mixing and the device is no longer functional in thearea proximate the short defect. There is no electrical shortthereafter, i.e., there is a “dead zone” created where the electricalshort once existed. This dead zone is an area where the material of theEC device still exists, but not in a functional form as in the bulk ofthe EC device. The material may be, e.g., melted to form small beads oruneven surface that diffuse the light passing through the substrate inthe area. When the EC device is colored, the area where the material waschanged is hard to discern because it is small (on the order of the sizeregime of a pinhole), but the transformed EC device material in thatarea, e.g., scatters the light that would otherwise pass through withoutbeing scattered or diffused.

In another embodiment, the energy source is configured and the energyapplied, such that the chemistry of the EC material in the areaproximate the short defect is changed so that the material ispermanently tinted and/or opaque. For example, many electrochromicmaterials require a particular oxidation state and/or stoichiometry ofmaterials (e.g. metal oxide to alkali metal cation) to be transparent.If heated to the proper temperature, oxygen can be driven off, cationscan be driven off and/or made immobile, and/or stoichiometries changedin order to permanently change the EC material to one that has a lower %T than the bulk EC device in the bleached state, be it transparent,translucent or opaque (having reflective and/or absorptive properties).

Thus as described above, one may modify the morphology of the ECmaterial, the chemistry, etc. in order to create a dead zone in the ECdevice that results in a less visually discernible or completelyobscured pinhole defect. In one embodiment, obscuring a pinhole byapplication of a material as described above is used in combination withmodifying the EC device material proximate a shorting defect in order toeffectively eliminate any visually discernible pinholes in an EC lite.

Thus far, the description has focused on applying a material to thepinhole to obscure it in some fashion and/or to modify the EC devicematerial proximate an electrical short defect in order to obscurepinholes or make less visually discernible pinholes. One might carry outthese operations when the EC device on the lite is available for directapplication of the obscuring material and/or when an energy source canbe applied to the EC device material without any intervening physicalstructure. For example, during fabrication of an EC lite, the lite istested for defects, any halos mitigated to form pinholes and thus thepinholes can be obscured using one or more methods described above,before the EC lite is incorporated into an IGU or laminated with anotherlite (e.g., where the EC device is within the laminate structure). But,if the EC lite is already incorporated into an IGU, where the EC deviceis on a surface inside the sealed space of the IGU, or the EC lite isincorporated into a laminate structure, then the surface bearing the ECdevice cannot be directly contacted in order to apply an obscuringmaterial to the pinholes and/or to apply an energy source to change theproperties of the EC device locally in order to produce a less visuallydiscernible pinhole. Embodiments described herein address suchsituations.

FIG. 6A depicts an IGU assembly, 600, having a first substantiallytransparent substrate, 605, a separator, 610, and a second substantiallytransparent substrate, 615. On the left of FIG. 6A is shown an explodedview of IGU 600 to indicate how the components are assembled. Alsoindicated are industry recognized numbers for each of the four substratesurfaces for a dual pane IGU construct. Surface 1 is the outer surfaceof the first lite, 605; surface 1 is the surface that is typically onthe outside of a building after the EC window is installed. Surface 2 isthe other side of the first lite, 605; that is, the surface of 605 thatis inside the IGU after the IGU is assembled. In this example, the ECdevice (not shown) is fabricated on surface 2 of lite 605. Surface 3 isthe surface of lite 615 inside the IGU, facing surface 2. Surface 4 isthe surface of lite 615 outside the IGU. When the three components arecombined, where separator 610 is sandwiched in between and registeredwith substrates 605 and 615, IGU 600 is formed. IGU 600 has anassociated interior space defined by the faces of the substrates incontact with the separator 610 and the interior surfaces of theseparator 610. Separator 610 is typically a sealing separator, that is,includes a spacer and sealing component (e.g. a polymeric adhesive suchas polyisobutylene (PIB)) between the spacer and each substrate wherethey adjoin in order to hermetically seal the interior region and thusprotect the interior from moisture and the like. The spacer and PIBcollectively define a primary seal. A typical IGU will also include asecondary seal, such as a polymeric sealant applied around the outsidethe primary seal, around the periphery of the spacer, but substantiallyin between the glass panes.

Substantially transparent substrates are typically used for EC lites.“Substantially transparent substrates” are of substantially transparentmaterial, for example, glass or Plexiglas. The substrates of the EClites of an IGU need not be made of the same material, for example, onesubstrate may be plastic while the other is glass. In another example,one substrate may be thinner than the other substrate, for example, thesubstrate that would face the interior of a structure, which is notexposed to the environment, may be thinner than the substrate that wouldface the exterior of the structure (e.g., building). In addition to anEC device coating, a substantially transparent substrate may furtherinclude a low emissivity coating, a UV and/or infrared (IR) absorber,and/or, a UV and/or IR reflective layer. The substrate type, e.g. glassor polymeric, and any additional coatings, are taken into account whenconsidering the following embodiments. For example, polymeric substratesmay or may not be transparent to laser radiation or other energy sourceused to obscure pinholes. This is described in more detail below.

FIG. 6B depicts a cross-section of IGU 600 as described in relation toFIG. 6A. FIG. 6B shows an EC device coating, 620, on surface 2 of theIGU. Surfaces 1 and 4 are indicated for reference. The interior regionof IGU 600 is typically, but not necessarily, charged with an inert gassuch as argon or nitrogen. Typically, the interior space issubstantially moisture free, that is, having a moisture content of lessthan about <0.1 ppm. Preferably, the interior space would require atleast about −40° C. to reach the dew point (condensation of water vaporfrom the interior space). Once the EC device is hermetically sealed inthe IGU, direct application of an obscuring material is not possible (onsurface 2 but of course, surface 1 would still be accessible). Also,methods described above that include application of laser light must beperformed through either substrate 605 or 615, rather than directly toEC device 620. Further embodiments for obscuring pinholes, methodsperformed after IGU fabrication or lamination, are described in moredetail below. Various embodiments take advantage of, and/or anticipatethe construction of an IGU and/or laminate in order to achieve theseends.

Referring to FIG. 6C, IGU 600 is depicted. Methods described above forobscuring a pinhole by changing the nature of the EC material using anenergy source, e.g. a laser, can be performed through substrate 605and/or substrate 615. For example, if the substrates are made of amaterial that is transparent to the laser energy, then the laser can beused to, e.g., change the morphology and/or chemistry of the EC materialof coating 620 by directing the laser beam through the substrates andonto the EC coating. An IGU having a reflective, absorptive, or othercoating(s) on one lite or the other must be accounted for when applyingthe energy to affect the desired result.

Additionally, as described above but e.g. through substrate 605 and/orsubstrate 615, substrate 605 may be modified on surface 2, e.g., at thebottom of a hole from ablation of a pinhole, where the substrate 605 ismodified to scatter or diffuse the light that would otherwise passthrough the hole without such scattering. In one embodiment, thesubstrate 605 is modified below surface 2, proximate the pinhole, inorder to scatter and/or obscure light that otherwise would pass throughthe pinhole above it. That is, using the correct focal length, power,etc., an energy source, such as a laser, is used to melt, ablate, changethe morphology of the substrate 605, e.g., glass, just below surface 2,inside the substrate 605, proximate the pinhole. For example, the lasermay be applied through surface 1 and not to the coating 620 itself, butto a position below surface 2. For example, the pinhole is created witha first laser pulse, and then a second laser pulse is used to form oneor more bubbles or other features just below surface 2, proximate thepinhole. In another example, the pinhole is created by a laser throughsubstrate 615, and the change in morphology just below surface 2 is madefrom another laser through substrate 605.

Though an EC device may be sealed inside an IGU or laminate, embodimentsto obscure pinholes are not limited to those where an energy source isused to modify an existing material in the EC device and/or substrate toscatter light or otherwise obscure a pinhole and/or create a lessvisually discernible pinhole. That is, in certain embodiments materialcan be added to the EC device surface to obscure a pinhole, even after alamination or IGU is constructed. Exemplary embodiments are describedbelow.

Before describing embodiments where material is used on the EC device toobscure a pinhole, after lamination and/or IGU formation, it isimportant to describe that in certain embodiments, material is added tosurfaces 4, 3 and/or 1, and/or surfaces 4, 3 and/or 1 are modifiedmorphologically, e.g., to scatter light, in addition to, oralternatively to, such modifications on surface 2. Such modificationsare within the scope of the embodiments disclosed herein, although it ispreferable to modify at or near surface 2 so as to minimize thepossibility that a pinhole will be seen from viewing the window at anangle. That is, modifications at surfaces other than surface 2 mayobscure a pinhole from certain, but not all viewing angles, and are thusless preferred. For example, surface treatments will have to affect alarger area in order to obscure a pinhole on surface 2 at wider viewingangles, and thus the larger area might be more noticeable and thereforeunattractive to the end user.

Referring again to FIG. 6C, in certain embodiments, material can beadded to the EC device surface to obscure a pinhole, even after an IGU600 is constructed. These methods can be performed, e.g., in the factoryafter IGU formation and testing, in the field after installation, orafter installation the IGU can be removed, sent to a facility formitigation and reinstalled in the field.

In one embodiment, a reagent gas is introduced into the IGU 600, e.g.via a breather tube or other similar gas exchange device. In oneembodiment, the seal 610 is penetrated in order to introduce the reagentgas. Once the void space 625 is occupied by the reagent gas, one or morelasers 630 are used to focus an energy pulse at the site of the pinhole.The laser (or other directed energy) supplies sufficient energy totransform the reagent gas into a solid material at the site of thepinhole, obscuring the pinhole. For example, the gas may be a monomer.Laser, ultraviolet or other energy is directed at the site of a pinholein order to polymerize the monomeric gas selectively only at the site ofthe pinhole. The pinhole is then obscured by the polymeric material.This process is repeated until all pinholes are obscured.

In one embodiment, while the IGU is filled with a reagent gas, e.g. amonomeric reagent that is polymerized upon exposure to an energy source,the energy source is applied via the pinholes while the EC device is ina tinted state. That is, the energy source is selectively introducedinto the IGU cavity by tinting the EC device and using the pinholes asaccess ports for the energy, e.g., a light source, UV lite, etc. Theenergy is directed at surface 1 and, since the EC device is tinted, theenergy passes only through the pinholes or only in sufficient quantitythrough the pinholes to convert the monomer to a polymer selectively atthe site of each pinhole. The polymerized monomer at the site of eachpinhole prevents further polymerization as the energy is blocked by thepolymerized material at the site of each pinhole. This embodiment hasthe advantage that all the pinholes are selectively concealed in asingle operation of applying the energy. The pinholes, by virtue of notcoloring, provide means for a highly selective polymerization only atthe sites of the pinholes when the EC device is tinted. In certainembodiments, e.g. on very large windows, it may be more convenient toapply the energy to smaller areas of surface 1, e.g. passing a wanddevice that emits the energy locally over the window, until all thepinholes are obscured. Detection of pinhole concealment may be donevisually, but can also be performed using an optical measurement device,e.g., where a specific level of concealment is desired. For example, thelevel of polymerization at a pinhole can be measured as a function ofthe amount of light passing through the pinhole as the energy is appliedto the pinhole. As the polymerization takes place, the light isprogressively blocked from passing through the pinhole. When asufficient level of light is blocked the energy application can beterminated. In one embodiment, the polymerization is self-limiting, asthe energy required for the polymerization is diminished by thepolymerization blocking the energy from entering the IGU cavity. In suchembodiments, the visual endpoint for pinhole concealment may beobviated. In one embodiment, the polymerization or other reaction toconceal the pinholes selectively is timed such that the desired level ofconcealment is achieved, e.g. either empirically or by knowing thereaction kinetics, by applying the energy for a specified time period.

After the pinhole(s) are obscured, the reagent gas is flushed from theIGU void space and replaced with argon or suitable inert gas and anyapertures are sealed to reestablish the integrity of the IGU seal. Theseembodiments have distinct advantages. For example, a large IGU, e.g., ina prominent display, is installed in the field. The IGU would be veryexpensive to replace. After a number of years, the IGU forms a halo inthe viewable area. The halo is very distracting to end users. Ratherthan uninstalling the IGU, a repair technician comes to the site. Aportable halo mitigation device is used to identify the shorting defectcausing the halo and mitigate the halo, e.g., using a laser to form apinhole. Such halo portable mitigation technology is described in U.S.provisional patent application, Ser. No. 61/534,712, filed Sep. 14,2011, and titled “PORTABLE DEFECT MITIGATOR FOR ELECTROCHROMIC WINDOWS,”naming Robert T. Rozbicki as inventor, which is herein incorporated byreference. After the technician transforms the halo to a pinhole, theend user may be satisfied with the result. Regardless, the technicianmay access the IGU void space, via a pre-installed breather tube, orpenetrating the IGU seal. The argon is flushed from the IGU using amonomeric gas. While the gas resides in the IGU, the technician againapplies energy, e.g. using the laser of the portable mitigation deviceor a UV source, to the site of the pinhole in order to selectivelypolymerize the monomeric gas at the site of the pinhole, thus obscuringthe pinhole. The monomeric gas is flushed from the IGU with argon andthe seal reestablished. The repair of the halo is complete and there areno visually discernible defects in the window. This result has beenachieved without having to remove the EC window from its installation,saving time, money and resources, while maximizing user enjoyment of thewindow.

Portable defect mitigation devices as described above have the advantageof having optical detection mechanisms to locate visual defects, andconvert them to pinholes via a mitigation mechanism, such as a laser.Also, such portable defect mitigation devices may include a memory, sothat the locations of the pinholes can be stored in the memory. Thislocation data can be further used for pinhole concealment as describedherein. The optical detection mechanism may be used to locate an opticaldefect and “better pinholes” be made via the mitigation mechanism.

Referring to FIG. 7, the methods described above can be performed on alaminated EC device as well. FIG. 7 depicts an EC device laminate, 700,which includes substrate, 705, having an EC coating, 720, thereon.Another substrate, 715, is laminated to substrate 705 via a transparentadhesive, 710. Adhesive 710 is in contact with the EC device in thisexample, which serves not only to hold the glass substrates together,but also as a protective covering for EC device 720. In the laminatestructure, there is no void space as in IGU 600. Nevertheless, energycan be directed to surface 2, just below surface 2, etc. as describedabove through substrates 705 and 715 (provided the lamination adhesivewill tolerate/pass the energy). In one embodiment, a halo is mitigatedfrom an EC device laminate 700 via directed energy through surface 1.After the halo is mitigated to form a corresponding pinhole, the pinholeis obscured by application of energy to the adhesive lamination materialin order to selectively change its properties proximate the pinhole inorder to obscure the pinhole. For example, laser energy may be used toselectively burn, darken, or otherwise change the optical properties ofthe adhesive proximate the pinhole.

Although the foregoing embodiments have been described in some detail tofacilitate understanding, the described embodiments are to be consideredillustrative and not limiting. It will be apparent to one of ordinaryskill in the art that certain changes and modifications can be practicedwithout avoiding the scope of the embodiments disclosed herein.

1. A method of mitigating a pinhole defect, the method comprising: a.providing an electrochromic lite having an electrochromic device on asubstrate; b. identifying a site of the pinhole defect in theelectrochromic device; and c. altering the site of the pinhole defect inorder to lower the light transmittance at the site of the pinholedefect.
 2. The method of claim 1, wherein c. comprises applying amaterial to the site of the pinhole defect, wherein the material has alower transmittance than the substrate.
 3. The method of claim 2,wherein the material is applied via an ink jet dispenser. 4-12.(canceled)
 13. The method of claim 2, wherein the material applied hasan opacity of about 50% of the maximum transmittance of theelectrochromic device.
 14. The method of claim 2, wherein the materialapplied has a color selected from a group consisting of white, black,gray, green, brown and blue.
 15. The method of claim 2, wherein thematerial applied comprises light scattering particles. 16-17. (canceled)18. The method of claim 2, wherein the material applied comprises athermochromic material.
 19. The method of claim 18, wherein thethermochromic material includes at least one of a leuco dye, an ink, apaint, a polymer and a metal oxide.
 20. The method of claim 19, whereinthe metal oxide includes at least one of titanium dioxide, zinc oxide orvanadium oxide.
 21. A method of claim 1, wherein identifying thenon-tinting area of the pinhole defect comprises identifying coordinatesof a short-related defect, mitigating the short-related defect via lasercircumscription to form the pinhole defect, and identifying the site ofthe pinhole defect based on the coordinates of the short-related defect.22. (canceled)
 23. The method of claim 1, wherein the pinhole defect iscreated by laser circumscription of a short-related defect in theelectrochromic device. 24-25. (canceled)
 26. The method of claim 1,performed after the electrochromic lite is incorporated into an IGU. 27.A method of claim 26, wherein c. comprises applying energy of a laser ona site of the pinhole defect; wherein the energy of the laser changestransmittance of the material at the site of the pinhole defect. 28.(canceled)
 29. A method of claim 26, wherein c. comprises (1)introducing a reagent gas into the interior volume of the IGU; and (2)applying energy from an energy source selectively at a site of a pinholedefect to transform the reagent gas into a solid material locally at thesite of the pinhole defect.
 30. The method of claim 29, wherein theenergy source is a laser or an ultraviolet light source.
 31. The methodof claim 29, wherein the reagent gas is a monomer which is polymerizedat the site of the pinhole defect upon application of the energy source.32. The method of claim 29, wherein b. and c. are repeated untilsubstantially all pinhole defects in the electrochromic device areobscured.
 33. The method of claim 29, wherein the energy source isapplied via the pinhole while the electrochromic device is in a tintedstate.
 34. The method of claim 32, wherein all the pinhole defects areobscured in a single application of the energy source.
 35. The method ofclaim 34, wherein the reagent gas is flushed from the IGU after thepinhole defects are obscured.
 36. The method of claim 35, wherein aninert gas is used to flush the reagent gas from the IGU.
 37. The methodof claim 1, performed after the electrochromic lite is incorporated intoa laminate.
 38. A method of claim 37, wherein c. comprises applyingenergy of a laser proximate an area of the pinhole defect in an adhesiveof the laminate; wherein the energy of the laser changes transmittanceof the adhesive proximate the pinhole defect.
 39. A method of visuallyobscuring a non-tinting area within the viewable area of anelectrochromic window comprising an electrochromic device on asubstrate, the method comprising: identifying the non-tinting area, saidnon-tinting area having a higher light transmittance than areas of theelectrochromic device in a tinted state; and applying a material to thenon-tinting area, wherein the material has a lower transmittance thanthe substrate.
 40. The method of claim 39, wherein the non-tinting areacomprises a pinhole.
 41. The method of claim 40, wherein identifying thenon-tinting area comprises identifying coordinates of a short-relateddefect, mitigating the short-related defect via laser circumscription toform the pinhole, and identifying the non-tinting area of the pinholedefect based on the coordinates of the short-related defect.
 42. Themethod of claim 39, wherein the material applied comprises athermochromic material.
 43. The method of claim 42, wherein thethermochromic material includes at least one of a leuco dye, an ink, apaint, a polymer and a metal oxide.
 44. The method of claim 43, whereinthe metal oxide includes at least one of titanium dioxide, zinc oxide orvanadium oxide.
 45. The method of claim 39, wherein the material appliedhas an opacity of about 50% of the maximum transmittance of theelectrochromic device.
 46. The method of claim 39, wherein the materialapplied comprises light scattering particles.
 47. The method of claim39, wherein the material is applied via an ink jet dispenser.
 48. Anelectrochromic window comprising: an electrochromic device coating on atransparent substrate; a non-tinting area in the viewable area of theelectrochromic window, the non-tinting area having a higher lighttransmittance than areas of the electrochromic device in a tinted state;a material applied to the non-tinting area, wherein the material has alower transmittance than the transparent substrate.
 49. Theelectrochromic window of claim 48, wherein the non-tinting area is apinhole.
 50. The electrochromic window of claim 48, wherein the materialapplied comprises a thermochromic material.
 51. The electrochromicwindow of claim 50, wherein the thermochromic material includes at leastone of a leuco dye, an ink, a paint, a polymer and a metal oxide. 52.The electrochromic window of claim 51, wherein the metal oxide includesat least one of titanium dioxide, zinc oxide or vanadium oxide.
 53. Theelectrochromic window of claim 52, wherein the material applied has anopacity of about 50% of the maximum transmittance of the electrochromicdevice.
 54. The electrochromic window of claim 53, wherein the materialapplied comprises light scattering particles.
 55. The electrochromicwindow of claim 54, wherein the material is applied via an ink jetdispenser.
 56. The electrochromic window of claim 55, wherein thematerial has a color selected from a group consisting of white, black,gray, green, brown and blue.